High hydrostatic pressure processing of murine norovirus 1-contaminated oysters inhibits oral infection in STAT-1(-/-)-deficient female mice.

We have previously demonstrated that high pressure processing (HPP) is effective in preventing in vitro replication of murine norovirus strain 1 (MNV-1), a human norovirus surrogate, in a monocyte cell line following extraction from MNV-1–contaminated oysters. In the present study, the efficacy of HPP to prevent in vivo replication within mice fed HPP-treated MNV-1–seeded oyster extracts was evaluated. Oyster homogenate extracts seeded with MNV-1 were given 5-min, 400-MPa (58,016-psi) treatments and orally gavaged into immunodeficient (STAT-1−/−) female mice. Mice orally gavaged with HPP-treated MNV-1 showed significant (P ≤ 0.05) weight loss leading to enhanced morbidity, whereas those given 100 and 200 PFU of HPP-treated MNV-1 were comparable to uninfected controls. MNV-1 was detected, via real-time PCR, within the liver, spleen, and brain of all mice fed non–HPP-treated homogenate but was not detected in the tissues of mice fed HPP-treated homogenates or in uninfected control mice. Hepatocellular necro...